BACTERIA- a single cell organisms. Well-known How do bacteria reproduce?

examples of bacteria include salmonella and binary fission the bacterium, which is a single cell,
staphylococcus bacteria. divides into two identical daughter cells .- begins when
Nomenclature of Bacteria - Refers to naming of bacteria the DNA of the bacterium divides into two (replicates)
and other organism which are named according to the
binomial system. Bacterial Diseases in Humans

TYPES OF BACTERIA Diseases of the Upper Respiratory Tract

Spherical: Bacteria shaped like a ball are called cocci, and 1.Streptococcal diseases (strep throat): are caused by
a single bacterium is a coccus. Streptococcus pyogenes,

Rod-shaped: These are known as bacilli (singular 2.Diphtheria is caused by a prophage-harboring strain of
bacillus). Some rod-shaped bacteria are curved. These Corynebacterium diphtheriae. As dead tissue
are known as vibrio. accumulates, a pseudomembrane forms in the throat or
nasopharynx.
Spiral: These are known as spirilla (singular spirillus). If
their coil is very tight they are known as spirochetes. 3. Pertussis (whopping cough) is caused by Bordetella
pertussis
Bacteria Structure
4. Bacterial meningitis is an inflammation of the
Capsule – some bacteria have this third protective membranes surrounding the brain and spinal cord. The
covering which is made up of polysaccharides; most infection can be caused by Neisseria meningitidis,
important role is to keep the bacterium from drying out Streptococcus pneumoniae, or Haemophilus influenzae.
and protect it from phagocytosis or engulfing by larger
microorganisms. Diseases of the lower Respiratory Tract

Cell wall – each bacterium is enclosed in rigid cell wall 1.Tuberculosis (TB) is caused by the acid-fast bacilli of
that gives its shape and surrounds the cytoplasmic Mycobacterium tuberculosis.
membrane, protecting it from the environment; the 2. "Typical" bacterial pneumonia is primarily caused by
strength of the wall is responsible from keeping the cells Streptococcus pneumoniae (pneumococcal pneumonia).
from bursting when there’s a large difference in osmotic Haemophilus influenzae, Staphylococcus aureus, and
pressure between cytoplasm and environment. Klebsiella pneumoniae are other species.
Plasma membrane – a layer of phospholipids and 3. "Atypical" bacterial pneumonia can be caused by
proteins that encloses the interior of the bacterium, Mycoplasma pneumoniae
regulating the flow of materials in and out of the cell.
Foodborne and Waterborne Bacterial Diseases
Nucleoid – region of cytoplasm where DNA is located.
1.Botulism is a severe form of food poisoning caused by
Cytoplasm – this is where the functions of cell growth, nerve toxins produced by Clostridium botulinum.
metabolism, and replication are carried out.
2.Salmonella Typhi is an acid-resistance bacillus that
Ribosomes – microscopic factories found in all cells; invades the blood. The infection is characterized by fever,
translate genetic code from the molecular language of abdominal pain, rose spots, lethargy, and delirium. -
nucleic acid to that of amino acids – the building blocks Typhoid vaccines are available and chloramphenicol is
of proteins which are the molecules that performs the the antibiotic of choice.
functions of cells and living organisms.
3. Vibrio cholerae infects the small intestines, producing
Flagellum – hairlike structure that provide a means of an enterotoxin causing profuse watery diarrhea and
locomotive function for those bacteria that have them; vomiting.
helps the bacteria to move away from toxic chemicals
and towards nutrients. Anthrax is an acute infectious disease caused by Bacillus
anthracis.
Pilus – hairlike projections (shorter) that assists the
bacteria in attaching to other cells and surfaces. Clostridium tetani is the causative agent of tetanus.

Bacteria Feeding Leptospirosis is a disease spread from animals to humans

(zoonosis by Leptospira interrogans. Infected individuals
Heterotrophic bacteria, or heterotrophs, get their have flu-like symptoms.
energy through consuming organic carbon. Most absorb
dead organic material, such as decomposing flesh. Some Syphilis caused by Treponema pallidum. Primary syphilis
of these parasitic bacteria kill their host, while others is characterized by a chancre.
help them.
Gonorrhea caused by Neisseria gonorrhoeae women
Autotrophic bacteria ( autotrophs) make their own may have symptoms of vaginal and urethral discharge of
food, either through either: photosynthesis, or pus and burning during urination.
chemosynthesis.
The Viruses
Photoautotrophs Bacteria that use photosynthesis
Viruses have : - helical - Icosahedral – Complex
Chemoautotrophs Those that use chemosynthesis These
Symmetry.
bacteria are commonly found in ocean vents and in the
roots of legumes, Viral Replication and Its Control 1. Attatchment 2.
Penetration 3.uncoating 4. Biosynthesis 5. Assembly 6.
Release
Corona Virus Replication and it’s Control FIRST LINE DEFENSE of nonspecific
Virus enters a cell 1. Skin and Mucous Membranes
Virus releases genetic code 2. Cellular and Chemical Factors
Genetic code converts to proteins 3. Microbial Antagonism
Proteins make copies
Viral parts get assembled The Skin Barrier - One of the body’s most important
Remdesivir blocks replication
physical barriers. Epidermis thin upper layer, dermis
Virus slows down
thicker layer and hypodermis layer of fatty tissue.
Viral Diseases of Humans Mucous Membranes which are composed of only a
Viral Infections of the Upper Respiratory Tract single layer of cells, also serve as a physical or mechanical
1. Influenza barrier to pathogens.
2. Sars - spread by person-to-person contact. Chemical Defenses the innate nonspecific immune
3. Herpes simplex describes a wide spectrum of system uses a number of chemical mediators that inhibit
viral diseases commonly found in the microbial invaders. Some are ENDOGENOUSLY and
environment. Infected MOTHER CHILD BIRTH. EXOGENOUSLY PRODUCED.
Another member of the herpesviruses is
varicella-zoster. This virus causes Chickenpox, EXAMPLE OF CHEMICAL DEFENCES
which is one of the most highly contagious Sebum type of ENDOGENEOUS MEDIATOR. Sebaceous
diseases.
glands in the dermis secrete an oil.
4. Measles Virus – member of the
oleic acid EXOGENOUSLY PRODUCED MEDIATOR
PARAMYXOVIRUSES.
because it is produced by resident microbes and not
5. Mumps
6. POLIO - permanent paralysis and muscle directly by body cells.
atrophy. Saliva - mediators such as lactoperoxidase enzymes, and
mucus secreted by the esophagus contains the
antibacterial enzyme lysozyme. - able to eliminate most
FUNGI – single cell or very complex multicellular
pathogens that manage to survive the acidic
organisms.
environment of the stomach.
TYPES OF FUNGI slight acidity of urine - the average pH is about 6.
Multicellular filamentous molds - inhibits the growth of many microbes and
made up of very fine threads (hyphae) hyphae keep potential pathogens in the urinary tract
growing and intertwining until they form a network of Lactate- EXOGENOUSLY PRODUCED chemical mediator
threads called a mycelium. in female reproductive system, to inhibit microbial
Digestive enzymes are secreted from the hyphal tip. growth.
Macroscopic filamentous fungi Cerumen (earwax) exhibits antimicrobial properties due
grow by producing a mycelium below ground. They differ to the presence of fatty acids,
from moulds because they produce visible fruiting bodies Chemical Factors
(commonly known as mushrooms or toadstools) that - The acidity of the stomach
hold the spores.
- The alkalinity of the intestines
Yeasts same size as red blood cells.
- The combination of stomach acid, bile salts, and
Fungal Diseases on Humans the rapid flow of the contents in the small
Fungal Nail Infections - technical name is intestines o mucous lining of the digestive tract
“onychomycosis.” - Peristalsis and the expulsion of feces
Ringworm caused by a fungus. It’s called “ringworm” - The low pH of vaginal fluid
because it can cause a circular rash (shaped Microbial Antagonism this occurs when resident
like a ring) that is usually red and itchy. “tinea” or microbes of the indigenous microflora prevent
“dermatophytosis.” “athlete’s foot.” colonization by new arrivals to a particular anatomical
Candidiasis infection caused by a yeast (a type of fungus) site.
called Candida.
SECOND LINE OF DEFENSE
LESSON 2 : DEFENSE MECHANISMS Transferin glycoprotein synthesized in the liver,
Interferons small, antiviral proteins produced by virus
Host defense mechanisms —are ways in which the body infected cells.
protect itself from pathogens —can be thought of as an Complement system biochemical cascade of the immune
army consistin of three lines of defense. system.
Fever inflammatory response that extends beyond the
Nonspecific host defense mechanisms are general and site of infection
serve to protect the body against many harmful Cytokines chemical mediators act that as chemical
substances. One of the nonspecific host defense is the messengers
innate, or inborn, resistance observed among some Phagocytes Defensive cells which help in eliminating
species of animals and some persons who have a natural microbes from the body.
resistance to certain diseases. Two main types
Neutrophil – primarily attacks bacteria;
Macrophage – means “big eater”; these cells eat,
ingest, or clean up mess of dead cells
Inflammation normal bodily response any local injury,
irritation, microbial invasion, or bacterial toxin.
Acute Inflammation response to tissue injury
Chronic Inflammation - When acute
inflammation is unable to clear an infectious
pathogen,
Pyrogens – effectively alter the “thermostat
setting” of the hypothalamus.

SPECIFIC DEFENSE MECHANISMS

Immunology
is the scientific study of the immune system and immune
responses.
When antigens enter our body, they stimulate a person’s
immune system to produce antibodies.
Immune system a silent wonder
A complex system that is responsible for protecting us
against infections and foreign substances.
Adaptive immunity
Specificity refers to the adaptive immune system’s ability
to target specific pathogens
Memory refers to its ability to quickly respond to
pathogens to which it has previously been exposed
B lymphocytes (B cells) produces antibodies which lock
unto the antigen of invading bacteria and immobilize
them until macrophages consumes them.
T lymphocytes (T cells) – killer cells

2major arms of the immune system:

Humoral immunity Mechanisms of adaptive specific
immunity that involve B cells and antibody production.
Cell-mediated immunity (CMI) The targeting and
destruction of intracellular pathogens by T cells